1. Lecture 9 Fragmented landscapes Landscape ecology Agroecology

3. Macropterous Carabidae Brachypterous Carabidae Dimorphic Carabidae Fragmented landscapes Idiosyncratic species Not nested High species turnover Slightly nested Moderate species turnover Highly nested Low species turnover Extinction driven system Random system Colonization driven system Colonization Persistence Nebria brevicollis Notiophilus biguttatus Carabus nemoralis Predictable species occurrences

4. Glanville fritillary Melitaea cinxia

5. The metapopulation of Melitaea cinxia

6. Mainland – island pattern Patchy regional distribution Patchy regional distribution without dispersal A combination of these patterns Different types of metapopulations

7. The Lotka – Volterra model of population growth Levins (1969) assumed that the change in the occupancy of single spatially separated habitats (islands) follows the same model. Assume P being the number of islands (total K) occupied. Q= K-P is then the proportion of not occupied islands. m is the immigration and e the local extinction probability. Immigration Emigration At equilibrium dP/dt = 0

8. The basic Levins model The basic function of the theory of island colonization of McArthur and Wilson The models describe changes in species numbers and occupancies in time The last model describes the changes occurrence probability on patch i at colonization rate  and extinction rate  Additional „canonical’ assumptions The basic model of metapopulation ecology describes the probability of occurrence in terms of mean patch distances d ij, the average migration distance , and the source island area A j

9. What does metapopulation ecology predict? Occurrences of Hesperia comma in fragmented landscapes in southern England (from Hanski 1994) Blue: occurrences Red absences Line: 50% chance to occur In fragmented landscapes occupancy declines nonlinear with decreasing patch area and with decreasing conncetivity There is a lower threshold of regional (metapopulation) extinction. This threshold can be predicted from the Levin’s model if species dispersal rates are known.

10. The fraction of occupied networks depends on the number of patches in a network. Bełow a certain threshold the species goes extinct. 0 0.2 0.4 0.6 0.8 1 010203040 Number of patches per network Fraction of occupied networks Data from the Glanville Fritillary redrawn from Thomas and Hanski (1997). Theoretical threshold

11. T R : regional extinction time T L : local extinction time K : regional number of patches p : Mean number of occupied patches Long term survival is only possible when the average proportion P/K of occupied patches is larger than 3 K -1 /2 : P > 3K 1/2 The model of Gurney and Nisbet (1978)(based on a stochastic form of the metapopulation model of Levins) predicts long term regional survival of a species if the average proportion of occupied patches is larger than 3 times K -0.5. Regional extinction times 0 200 400 600 800 1000 1200 01234567 P K 0.5 Median time to extinction

12. Local time to extinction Years15102050 Species OccurrencesRegional time to extinction Carabus granulatus 132.23327E+181.11664E+192.23327E+194.46655E+191.11664E+20 Pterostichus melanarius 132.23327E+181.11664E+192.23327E+194.46655E+191.11664E+20 Pterostichus strennus (Panzer) 132.23327E+181.11664E+192.23327E+194.46655E+191.11664E+20 Oxypselaphus obscurus (Herbst) 12264891221301.32446E+112.64891E+115.29782E+111.32446E+12 Pterostichus diligens (Sturm) 113704282185214103704282074085640185214099 Synuchus vivalis (Illiger) 10220261101322202654405291101323 Patrobus atrorufus (Stroem) 10220261101322202654405291101323 Pterostichus antracinus 9854427085411708142703 Pterostichus minor (Gyllenhal) 9854427085411708142703 Carabus nemoralis Muller 9854427085411708142703 Notiophilus palustris (Duftshmid) 7211072144281069 Clivina fossor (Linnaeus) 7211072144281069 Stomis pumicatus (Panzer) 7211072144281069 Leistus rufomarginatus (Duftshmid) 53173570175 Epaphius secalis (Paykull) 53173570175 Notiophilus biguttatus (Fabricius) 317152973 Calathus melanocephalus (Linnaeus) 317152973 Calathus mollis (Marsham) 115102152 Dischirius globosus (Herbst) 115102152 Leistus ferrugineus (Linnaeus) 115102152 Carabus hortensis Linnaeus 115102152 Calathus micropterus (Duftschmid) 115102152 Calathus fuscipes (Goeze) 115102152 Carabus cancelatus Illiger 115102152 Extinction times of Mazuran ground beetles Local extinction times are roughly proportional to local abundances

13. SPOMSIM

14. Today’s reading Metapopulation: http://en.wikipedia.org/wiki/Metapo pulation http://en.wikipedia.org/wiki/Metapo pulation Metapopulation research group: http://www.helsinki.fi/science/meta pop/ http://www.helsinki.fi/science/meta pop/ Metapopulation and extinction: http://faculty.plattsburgh.edu/thom as.wolosz/metapop.htm http://faculty.plattsburgh.edu/thom as.wolosz/metapop.htm Landscape ecology: The state of art http://www.edc.uri.edu/nrs/classes/nrs534/ NRS_534_readings/Turner_AnnRevEcoSy s_2005.pdf